282 



THE LARYNX. 



is somewhat compressed laterally, so that the passage through it is 

 here elliptical. 



The arytenoid cartilages (figs. 188, 189, a) are two in nmnber, and 

 are symmetrical on each side. They may be compared to three-sided 

 pyramids recurved at the summit, resting by their bases on the posterior 

 and highest part of the cricoid cartilage, and with their tips aj^proaching 

 one another. Each measures five to six lines in height, about three 

 in width, and, in the middle of its inner surface, rather moi*e than a line 

 from before backwards. Of the three faces the posterior is broad, trian- 

 gular, and excavated from above downwards, lodging part of the aryte- 

 noid muscle. The anterior, convex in its general outline, and somewhat 

 rough, gives attachment to the thyro-arytenoid muscle, and, by a small 

 tubercle, to the corresponding superior or false vocal cord. The 

 internal surftice, which is the narrowest of the three, and slightly con- 

 vex, is nearly parallel with that of the opposite cartilage, and is covered 

 by the laryngeal mucous membrane. The anterior and posterior 

 borders, which limit the internal face, ascend nearly in the same vertical 

 plane, whilst the external border, which separates the anterior from the 

 posterior surface, is directed obliquely upwards and inwards. 



The Jiasc of each arytenoid cartilage is slightly hollowed, having 

 towards its inner part a smooth surface for articulation with the cricoid 

 cartilage. Two of its angles are remarkably prominent, viz., one 

 external, short, and rounded, which projects backwards and outwards, 

 and into which the posterior and the lateral crico-arytenoid muscles 

 are inserted ; the other anterior, which is more pointed, and forms a 

 horizontal projection forwards, to which the corresponding true vocal 

 cord is attached. 



The apex curves backwards and a little inwards, and terminates in a 



Fig. 189. Fig. 189.— Outline siiowing the 



Position and Form op the Ary- 

 tenoid Cahtilages from behind. 

 One-half the Natural Size. 

 /(, liyoid Lone ; t, the superior, ami 

 t', the inferior cornu, of the thyroid 

 cai-tilage ; c, placed on the median 

 ridge of the back of tlie cricoid carti- 

 lage ; «, placed between the two ary- 

 tenoid cartilages, to which the letter 

 points by two dotted lines ; the carti- 

 lages of Santorini or cornicula are 

 shown above the upper angles ; t r, the 

 trachea. 



blunt point, which is sur- 

 mounted by a small cartila- 

 ginous appendage nanii^d 

 " corniculum laryngis." 



The cornicula laryngis, 

 or cartilages of Santorini 

 are two small yellowish carti- 

 laginous nodules of a some- 

 what conical shape, which are 

 articulated with the summits of the arytenoid cartilages (fig. 189), and 

 serve as it were to prolong them backwards and inwards. They 

 sometimes form part of the arytenoid cartilages. 



